在与圆有关的图形中,求锐角的三角函数值,是常见的题形.本文以近几年的中考题为例,对其解法作一归纳.一、在直角三角形中,利用锐角三角函数定义求值例1(2012年襄阳市)如图1,PB为⊙O的切线,B为切点,直线PO交⊙O于点 In the circle-related graphs, finding the trigonometric values ​​of acute angles is a common problem.This paper takes the test questions in recent years as an example to make a generalization of the solution.First, in the right triangle, the definition of acute trigonometric functions Example 1 (Xiangyang City in 2012) As shown in Figure 1, PB is the tangent of ⊙O, B is the tangent point, and the straight line PO intersects ⊙O at point